Igniter for internal-combustion engines



1966 E. SCHNIERING ETAL 3,279,448

IGNITER FOR INTERNAL-COMBUSTION ENGINES Filed Nov. 23, 1964 Ernsf Schniering Heinrich W. N. Wesfermann INVENTORS.

Fig.3

AGENT.

United States Patent 3,279,448 IGNITER FOR INTERNAL-COMBUSTION ENGINES Ernst Schniering, Auf dem Schoolbruch 28, Gelsenklrchen-Horst, Germany, and Heinrich Wilhelm Nieder Westermann, Lennestrasse, Essen, Germany Filed Nov. 23, 1964, Ser. No. 413,375

Claims priority, application Germany, Nov. 22, 1963,

Sch 34,202 5 Claims. (Cl. 123143) Our present invention relates to an igniter adapted to be mounted, in the manner of conventional spark or glow plugs, in a combustion chamber of an internal combustion engine for periodically triggering an explosion of an air/fuel mixture therein.

Electrically operated igniters, of the types mentioned above, require relatively complex circuitry for their energization. Failure of the power supply, moreover, inhibits the ignition process and causes stalling of the engine.

The general object of our invention is to provide an igniter for the purpose described which does not require a source of electric current for its operation and which may be used with a variety of internal combustion en gines, including those of the carburetor and the injector type.

A more particular object of our invention is the provision of means in such an igniter for advancing or retarding the timing of the ignition, in the manner usual in automotive vehicles, without electric controls.

The foregoing objects are realized, in accordance with our invention, by the provision of an igniter which in its external dimensions and appearance may be similar to a conventional spark plug and which comprises two relatively reciprocable members, such as a housing and a plunger, defining between them a variable ignition space which communicates with the ambient atmosphere in a position of maximum volume but is cut off from that atmosphere in a position of minimum volume into which the members are brought in response to ambient pressure. Thus, the plunger may be designed as a differential piston movable in an open-ended housing of generally cylindrical configuration mounted in a wall of the combustion chamber; the same effect, however, is realizable with kinematic reversal of the parts, thus with a stationary inner member or plunger and a pressure displaceable outer member or housing. Advantageously, the device also includes biasing means (such as a compression spring) tending to maintain the two members in a position of greatest separation in which the variable space communicates with one or more access ports for the ambient gas mixture; as the gas pressure in the combustion chamber rises, the two members are relatively displaced against the biasing force toward a position of closest approach with blocking of the access port or ports in the course of the displacement stroke. The ignitable gas mixture now entrapped in the ignition space is thereupon further compressed until its flash point is reached, the ensuing explosion reversing the relative displacement of the members until communication is reestablished with the combustion chamber into which the flame now passes through the access ports to initiate the main combustion. The ignition space is then substantially evacuated during the following exhaust stroke of the engine so as to be ready to receive part of the ignitable mixture thereafter admitted into the combustion chamber.

The timing of the ignition may be varied in several ways, as by altering the stress of the biasing spring or changing the maximum volume of the ignition space. The timing control may in either case be carried out either manually or automatically, e.g. through a suitable ice linkage with the tachometer or the accelerator pedal of a vehicle powered by the engine.

The invention will be described hereafter in greater detail with reference to the accompanying drawing in which:

FIG. 1 is an axial sectional view of an ing the invention;

FIG. 2 is a view similar to FIG. 1, showing another embodiment; and

FIG. 3 is another view similar to FIG. 1, showing a modification of the embodiment of FIG. 2.

In FIG. 1 we have indicated at 20 a wall of a combustion chamber 21, formed within a cylinder, not further illustrated, of a conventional automotive internal combustion engine. An igniter according to our invention comprises a generally cylindrical housing 1, threadedly secured to the wall 20, having a plunger 4 with a head 4a reciprocable therein so as to define a variable ignition space 2 in the interior of the housing. A screw cap 8 engages the open lower end of the housing, facing the combustion chamber 21, and defines a bottom stop for the plunger 4 which is downwardly biased by a compression spring 5 abutting a screw 6, the latter being threadedly received in the top of housing 1 for adjustment of the spring pressure. Plunger 4 is formed with several passages 3, 3' connecting the space 2 with a recess 7 on the underside of head 4a in the bottom position of the plunger in which the volume of space 2 is at its maximum. It will be apparent that any rise of piston 4 over only a fraction of stroke length will block the passages 3 so as to shut off communication between the space 2 and the combustion chamber 21.

It will be noted that the head 4a has a lower surface area, facing the chamber 21, which is larger than its upper area facing the space 2 so that this head acts as a differential piston as long as the passages 3 are unblocked to act as access ports for the air/fuel mixture admitted into chamber 21 by the usual means. As the gas pressure in chamber 21 rises, head 4a responds to this pressure in the manner of a differential piston so that plunger 4 is driven upwardly to block the passages 3. The gas pressure in chamber 21 now acts only upon the exposed lower face of the plunger which continues its ascent to compress the gas mixture entrapped in space 2 until the flash point of that mixture is reached; at this instant the mixture explodes and drives the plunger 4 downwardly, with release of the burning gases from space 2 into chamber 21 as soon as the ports 3 have become again unblocked. The flame from space 2 now ignites the main gas volume in chamber 21 to initiate the explosion stroke of the engine.

Since the rate of inward displacement of plunger 4 igniter embodywill depend on the pressure exerted by the spring 5, the

timing of the ignition may be advanced or delayed by adjusting the position of screw 6. This can be done manually or automatically, e.g. in dependence upon the fuel supply or the engine speed, as illustrated schematically in FIG. 1 where we have shown the screw 6 coupled by way of example with a pinion 15 in mesh with another pinion 16 rotatable by a control lever 17; the latter could be suitably linked with a gas pedal or with a centrifugal governor driven by the engine.

FIG. 2 shows a housing 1 with a plunger 4 in the form of a stepped piston head having a flange 9 received in an annular recess 10 of the housing, this recess being bounded by a bushing 11 threadedly inserted into the housing 1' from above to permit removal of the plunger. A disk 12 is threadedly engaged by a rod 6' whose lower extremity penetrates into an axial bore of piston head 4' to define with it the variable ignition space 2. Head 4' has a plurality of passages 3' opening into the space 2 in the illustrated bottom position, these passages being blocked by the rod 6 as soon as the piston head begins to rise against the pressure of a biasing spring bearing upon the disk 12. Rod 6 may be axially adjusted, either manually with the aid of a screwdriver slot 18 or automatically as described with reference to rod 6 of FIG. 1,

for the purpose described with reference to FIGS. 1 and 2. Space 2 normally communicates with the exterior of housing 1" through a central port 3 in the otherwise closed bottom of plunger 4". Upon a rise of the plunger under ambient gas pressure, as previously described, port 3 is blocked by a stud 14 axially projecting from the lower extremity of rod 6".

The operation of the devices of FIGS. 2 and 3 is, of course, analogous to that described with reference to the embodiment of FIG. 1.

Departures from the arrangements specifically described and illustrated are, of course, possible within the spirit and scope of our invention as defined in the appended claims.

We claim:

1. An igniter adapted to be mounted in a combustion chamber of an internal combustion engine for periodically triggering an explosion in said chamber, comprising:

a generally cylindrical housing having an open end;

a plunger reciprocable in said housing adjacent said open end;

means including said plunger defining within said housing a substantially closed space of Variable volume reducible to a minimum upon inward displacement of said plunger, said means further forming at least one port connecting said space with the exterior of said housing in a relatively withdrawn position of said plunger corresponding to a maximum volume, said plunger having a piston head with a larger area facing said open end and a smaller area facing said space, said port being blocked upon inward displacement of said plunger in response to ambient pressure differentially acting upon said head whereby the pressure of an ignitable mixture in said space is raised to the flash point of said mixture, the ensuing ignition of said mixture increasing the relative separation of said plunger and housing with unblocking of said port for release of the burning mixture from said space; and

biasing means bearing upon said plunger in a sense urging it outwardly with reference to said housing, said biasing means comprising a compression spring with adjustable pressure for varying the timing of said ignition.

'2. An igniter adapted to be mounted in a combustion chamber of an internal combustion enginne for periodically triggering an explosion in said chamber, said igniter comprising:

a generally cylindrical housing having an open end;

a plunger reciprocable in said housing adjacent said open end;

a rod provided in said housing; and

means including said plunger and said rod defining within said housing a substantially closed space of variable volume reducible to a minimum upon inward displacement of said plunger, said means further forming at least one port connecting said space with the exterior of said housing in a relatively withdrawn position of said plunger corresponding to a maximum volume, said plunger having a piston head with a larger area facing said open end and a smaller area facing said space, said head being provided with a cylindrical bore substantially closed at one end, said rod being matingly received in said bore for defining said space between an extremity of said rod and said substantially closed end, said port being formed in said head and being blocked upon inward displacement of said plunger in response to ambient pressure differentially acting upon said head whereby the pressure of an ignitable mixture in said space is raised to the flash point of said mixture, the ensuing ignition of said mixture increasing the relative separation of said plunger and housing with unblocking of said port for release of the burning mixture from said space.

3. An igniter as defined in claim 2 wherein said rod is adjustably mounted in said housing for varying the size of said space, thereby altering the timing of said ignition.

4. An igniter as defined in claim 2 wherein said port is formed in said substantially closed end, said extremity having a projection receivable in said port for blocking same upon inward displacement of said plunger.

5. An ignite-r as defined in claim 2, further comprising biasing means bearing upon said plunger in a sense urging it outwardly with reference to said housing.

References Cited by the Examiner I UNITED STATES PATENTS 973,65 1 10/ 1910 Haberkorn 123143 1,466,943 9/ 1923 Ball et al. 123-143 1,474,661 1 l/ 1923- Berglox 123-443 FOREIGN PATENTS 515,717 1/1931 Germany. 933,902. 10/1955 Germany.

232,603 11/ 1925 Great Britain.

MARK NEWMAN, Primary Examiner. L. M. GOODRIDGE, Assistant Examiner. 

1. AN IGNITER ADAPTED TO BE MOUNTED IN A COMBUSTION CHAMBER OF AN INTERNAL COMBUSTION ENGINE FOR PERIODICALLY TRIGGERING AN EXPLOSION IN SAID CHAMBER, COMPRISING: A GENERALLY CYLINERICAL HOUSING HAVING AN OPEN END; A PLUNGER RECIPROCABLE IN SAID HOUSING ADJACENT SAID OPEN END; MEANS INCLUDING SAID PLUNGER DEFINING WITHIN SAID HOUSING A SUBSTANTIALLY CLOSED SPACED OF VARIABLE VOLUME REDUCIBLE TO A MINIMUM UPON INWARD DISPLACEMENT OF SAID PLUNGER, SAID MEANS FURTHER FORMING AT LEAST ONE PORT CONNECTING SAID SPACE WITH THE EXTERIOR OF SAID HOUSING IN A RELATIVELY WITHDRAWN POSITION OF SAID PLUNGER CORRESPONDING TO A MAXIMUM VOLUME, SAID PLUNGER HAVING A PISTON HEAD WITH A LARGER AREA FACING SAID OPEN END AND A SMALLER AREA FACING SAID SPACE, SAID PORT BEING BLOCKED UPON INWARD DISPLACEMENT OF SAID PLUNGER IN RESPONSE TO AMBIENT PRESSURE 